Invasive Species Council of British Columbia

Sampling Biodiversity in the Schoolyard 

Grade: 9 to 12

Duration: 3 or more hours

Setting: Indoor/outdoor

Subjects: Math, Science

Physical Activity: Yes

Students will conduct field investigations using a quadrat area study method to analyze the abundance, density, distribution, and biodiversity of plants growing in their schoolyard. They will learn how to use quadrats and datasheets in the field while maintaining their safety and protecting the habitat they are studying. Students will demonstrate a knowledge of common plants by using field guides or ID apps to determine what native and invasive species are growing in the study area. Students can contribute to community science by observing and reporting invasive species using the iNaturalist and Report Invasives apps. Back in the classroom, the students will interpret and communicate their findings with an analysis and discussion. 

Related Activities 

Mapping Biodiversity Changes 

Inquiry Questions 
  • What is biodiversity and why is it important? 
  • What is the distribution and abundance of plants growing in my schoolyard? 
  • What are the impacts of invasive species on native species and habitats? 
  • How do people monitor and manage invasive species? 
  • How can I take action to remove invasive species and restore native habitats? 
BC Curriculum Links  

Science Big Ideas 

  • Organisms are grouped based on common characteristics (Life Sciences 11) 
  • Complex roles and relationships contribute to diversity of ecosystems (Environmental Science 11) 
  • Humans can play a role in restoration and stewardship of ecosystems (Environmental Science 11) 
  • Biodiversity is dependent on the complex interactions and processes between biotic and abiotic factors. (Specialized Science 12) 

Science Curricular Competencies (Grades 9-12) 

  • Make observations aimed at identifying their own questions about the natural world 
  • Collaboratively and personally plan, select, and use appropriate investigation methods, including field work and lab experiments, to collect reliable data (qualitative and quantitative) 
  • Experience and interpret the local environment 
  • Seek and analyze patterns, trends, and connections in data, including describing relationships between variables, performing calculations, and identifying inconsistencies 
  • Evaluate their methods and experimental conditions 
  • Consider social, ethical, and environmental implications of the findings from their own and others’ investigations 
  • Contribute to finding solutions to problems at a local and/or global level through inquiry 
  • Express and reflect on a variety of experiences, perspectives, and worldviews of place 

Math Big Ideas 

  • Analyzing the validity, reliability, and representation of data enables us to compare and interpret. (Math 9) 
  • Representing and analyzing situations allows us to notice and wonder about relationships. (Foundations of Math, Pre-Calculus 10) 
  • Statistical analysis allows us to notice, wonder about, and answer questions about variation (Foundations of Math 11) 

Math Curriculum Competencies (Grades 9-12) 

  • Explore, analyze, and apply mathematical ideas using reason, technology, and other tools 
  • Apply flexible and strategic approaches to solve problems 
  • Engage in problem-solving experiences connected to place  
  • Communicate mathematical thinking in many ways 
  • Connect mathematical concepts to each other and to other areas 
  • 10m tape measure or 10m marked string/rope (quantity of either =2) 
  • 1m x 1m quadrat frame or create your own quadrats using string. (Hula hoops can also be used as quadrat frames) 
  • If making string quadrats, you will need the following (see Documents to Download and Additional Resources for video link)  
  • 4.25m lengths of string marked at each 1m (1 per group, 3-4 students in a group) 
  • 4 pencils or chopsticks per group  
  • Permanent marker 
  • Clipboards with pencils (1 per group) 
  • Something to draw numbers out of (such as a hat or bowl) with numbers 1-10 on small pieces of paper (or use a random number generator). 
  • Native and invasive species ID guides or apps. (See Additional Resources for suggestions)  
  • Hand lenses (optional) 
  • Cameras/ cell phones for images 
Documents to Download 

Belt Transect (Optional Extension or Alternative Sampling Method) 

What are invasive species and their impacts? 

A native species is one that has lived and evoled in a given place for a long time, and is part of the natural ecosystem. They have adapted to local conditions, and co-evolved alongside other species, predators, diseases, and climate factors. An invasive species is a fast spreading non-native organism that has been indroduced to an environment from other areas that causes economic, environmental or social harm. Not all non-native species are invasive and many non-native species are important in society. For example, many of our foods, such as tomatoes, wouldn’t survive outside a well-tended garden. For more information on invasive species and their impacts, read Background on Invasive Species for Educators

Biodiversity is the variety of life in a given area. Two measures of biodiversity are species richness (the number of different species in an area), and species evenness (the relative abundance of each different species). Consider Area 1 with 2 frogs, 1 cat, 3 maple trees, and 6 fern plants and Area 2 with 4 frogs, 4 cats, 4 maple trees and 4 fern plants. Both areas have a species richness of 4, but the Area 2 has a higher species evenness because all species have the same abundance and therefor Area 2 has a higher biodiversity. 

Invasive species are the 2nd greatest threat to biodiversity after habitat loss. Invasive animals feed on native species, and invasive plants displace native plants through competition for water, nutrients, and space. Invasive species decrease both the species richness and the species evenness of natural ecosystems, which threatens many rare and endangered species and could potentially drive them to extinction. More biodiverse ecosystems are less susceptible to invasions. More species may represent more ecological niches, and with fewer native species present there are more opportunities for an invasive species to fill a niche in the ecosystem and impact it.   

The importance of inventory, monitoring, and following established protocols 

Inventory and monitoring are methods that help determine what species are in an area. These studies can be compiled and analyzed over time to detect changes to the biological composition of an area such as the introduction of invasive species, and they can also show how one site compares to other sites in a region. These studies are valuable to scientists, land managers, and concerned citizens, especially when used for invasive especies removal and management. People who are restoring an area need to know the locations of specific invasive species, whether they are spreading, and the effectiveness of invasive species management practices. Inventories help provide this information. 

There are different types of inventories. Sometimes, an inventory covers a large area in a broad sweep. Other inventories provide detailed information about a small area. Regardless of the type, it is important that the information or data collected during the inventory is accurate and reliable. To ensure the reliability of information, there are strict protocols to follow when collecting field data. It is important to record key data such as date, time, location, and weather so there is always a reference to look back on. 

Types of sampling methods  

Monitoring of plant life – both native and non-native – can be done several ways, including random sampling and systematic sampling. Random sampling works well when estimating the population of species of a distinct, easily accesible area. Systematic sampling works well when assessing a pattern in an area. Both methods generate information about the kinds of species found in an area and their abundance, distribution, and density.  

In simple random sampling, every area has an equal chance of being chosen. A quadrat area survey is used to assess what kinds of plants live in an area to estimate their population. A quadrat is either a rectangle, square, or circlular frame that ranges in size depending on what and where you are studying. The area inside the quadrat can also be refered to as a plot. The quadrats that the students use will designate the boundaries of where each group will count the plants in the schoolyard.Within the designated area, quadrats will be randomly placed in which to count the species. From there, population estimates of the larger area can be made based on the multiple quadrat samples. 

In systematic sampling, a certain area is measured in a non random and consistent way. One way to do this is with a belt transect. They work by using quadrats along a transect line and counting the individuals within the quadrat. Students can use the belt transect method to assess if the abundance of plants changes from a distubed area (such as a path) to a less disturbed area. See the extension “Belt Transect” if you wish to add this to the lesson. 

Contribute to community science using observing and reporting apps  

Reporting species you observe is critical for the protection of BC’s biodiversity from the spread of invasive species. Reporting can help detect new infestations of invasive species, particularly those capable of significant environmental, economic, and social harm. As well, reporting native species observations is important for biodiversity protection. Reporting observations will help the scientific community identify and manage invasive species and protect BC’s natural spaces. 

It is easy to report with iNaturalist and the Report Invasives apps. Students can use these apps during this lesson to identify the native and invasive plants they find in their quadrats. It is not necessary to have cellular data or a wifi connection to collect the information as it will save and upload automatically once back online.. Or, if students have an image of the species, they can upload it to the apps when in wifi. If it isn’t possible for students to have their own iNaturalist account, teachers can create an account and all students can each contribute observations to the adult account. If using the iNaturalist app, make sure to join the I Spy and Identify Project and join the active community of people observing nature and protecting Canada’s outdoor spaces by contributing to Canada’s biodiversity science. 

  1. Look for a 10m x 10m area in which to run your activity. Aim for an area with many different plant species (students will not be counting grass or moss). If there are no plant identification guides or resources available to you, you could photocopy the common plants in your schoolyard to create your own field guide. 
  2. Look for any hazards on site, such as steep or uneven terrain, signs of wildlife in the area, or toxic plants. 
  3. Gather materials and Documents to Download 
  1. Introduce the background information to this lesson.  
  2. Download the iNaturalist and Report Invasive apps.  
  3. Explain what the students will be doing in the classroom and in the field. 
  4. Review with students “The Datasheet- Cheat Sheet” (see Documents to Download) as it describes what each group will be recording on their datasheet. 
Prior to going outdoors: 
  1. Divide students into groups of 2 or 3 students. 
  2. Give materials to each group: one quadrat or string quadrat materials, datasheet/clipboard/writing utensil.  If available, each group could also have a magnifier, field guide or tablet/phone to take photographs.  
  3. Groups will choose 2 numbers from a hat/bowl with numbers 1-10 inside. Ensure they put the number back into the hat/bowl after every draw but ensure that no 2 groups have the same location in the study area. Students will write those numbers on their datasheet; this will be their location in the study area in which to place their quadrat for sampling. 
In the field: 
  1. The class will create a study area of 10m x 10m using the tape or measured string at a 90-degree angle (can use a book corner to ensure 90). 
  2. Groups will fill in the first page of their group datasheet, including a rough sketch of the study area.  
  3. For each group, one student will stand on one of the 10m lines at the meter mark of one of the numbers they pulled out of the hat/bowl, and another student of the same group will do the same on the other 10m line for the second pulled number. 


  1. They will move out in as straight of a line as they can to meet each other, and this location will be where the group will lay their quadrat and start counting. 
  2. Groups will set up their quadrat and try their best to keep the quadrat parallel with the study area border as above. 
  3. Once they have their quadrat set up (if using the string quadrat – see the How to Create a String Quadrat or YouTube video for instruction), ask students to take a bird’s-eye photo of their quadrat and/or sketch it in the corresponding spot on page 2 of the Group datasheet. 
  4. Each group will fill the “in the field” section on the second page of their group datasheet by counting individual plants (ensure students are counting individuals, not multiple stems/leaves/flowers of the same plant as individuals) and assessing the plants within their quadrat. Remind them that they will not be counting grass or moss (as these may be too numerous to count.  Groups could instead make qualitative notes on the presence and estimated abundance or percent cover of grass or moss in the quadrat.)  Students should refer to the Datasheet- Cheat Sheet for more details on how to fill out the group datasheet.  
  5. Students can identify plant species using field guides and ID apps. They can observe closely (use magnifiers, if available), and notice differences between plants, noting and describing “Plant A” “Hairy-stemmed Plant”, “Green and white clover”, etc, until plants can be identified.  Ask students to take photos of each species of plant to help with identification. It is recommended to use the iNaturalist app to identify plants, and the Report Invasives app to report any invasive plants that they see. They can also take the photos of the plants they captured and upload them to iNaturalist and Report Invasives when they are back in the classroom. 
  6. Students can also use other plant ID resources if they are available.


Back in the classroom: 

Students will fill the “in the classroom” section on the second page of their group datasheets to calculate relative abundance and density of the different plants recorded in their quadrat.  Once this is completed, the class datasheet can be filled out either as a class, per individual student or per group. 

Data Analysis 
  1. Refer to the Datasheet – Cheat Sheet for explanations on how to collect and analyze data.  
  2. Determine percentages of native and non-native plants found within the study area using the estimated total populations: 

(sum of total populations of native species) ÷ (sum of all total populations) × 100% 

(sum of total populations of non-native species) ÷ (sum of all total populations) × 100% 

  • Another optional calculation to do as a class is the Shannon Diversity Index, which is a way to measure the diversity of species in a community. The minimum value of the Shannon diversity index is 0 – this would indicate no diversity – with only one species found in that habitat.  The higher the value, the higher the diversity.  In this calculator, evenness is a percentage of how even the community is as a whole. There are also instructions on how to calculate the Shannon diversity index using the mathematical equation. Click the “Shannon diversity index’s range of numbers” option beside the calculator for more explanation of the numerical outcome. 
  1. Consider other ways to summarize the class data, such as by pie or bar graphs along with photographs or sketches of the study area and plants observed. 
Discussion Questions 
  • Consider the methods that were used in this study.  Why do you think it is preferred to use quadrats to sample an area rather than counting every plant in the study area? 
  • What plants were most common in your study area? Least common?  How do you your results would compare to nearby parks or other green spaces?   
  • Consider your study area’s species richness and evenness. Do you think that your study area is biodiverse? Why or why not?  
  • Is there a relationship between species richness and evenness (biodiversity) and the abundance of invasive species in the study area? If so, what do you notice?  
  • Why is averaging the species abundance useful when estimating total populations? How different would the estimate of total populations be if you estimated only using the numbers you found in your quadrat? 
  • Make hypotheses to explain the patterns that are revealed by the data. For example, you may notice that an invasive plant dominates one area. Your hypothesis might be that there is more disturbance and trampling near a trail or path or picnic table and invasive species are able to withstand these disturbances better than some other plants. 
  • What could be done to enhance biodiversity or prevent the spread of invasive species found in the study area? 
  • Try another method of sampling using the Belt Transect Study (description and datasheets are in the Documents to Download section).  In a belt transect, quadrats are laid down in a regular, systematic fashion along a sampling line, rather than at random. This method can reveal differences in plant abundance and diversity along a gradient, such as the distance away from a trail or road.   
  • Research some of the plants found in your study. Each student could research a single invasive species observed in your region and write a short paper or create a poster describing where it is native to, how it got here and when it arrived, its impacts to native wildlife and habitat, and how its spread is being managed or can be prevented. 
  • Develop an action project based on your study.  Determine what invasive species should be managed, complete with research on the best practices on when and how to remove them, safety precautions, and the best native or naturalized plants to plant instead.. To add to this, you could also create a monitoring plan for the area once the restoration has been done using another quadrat area study. 
Additional Resources 
  • Grow Me Instead: Native and non-invasive alternatives to plant in the garden.   
  • Identification Tools and Field Guides 
  • NatureScape guides are also available for each region in BC, with specific information on native plants and animals from that region.  Find your regional NatureScape guide here.  
  • Observe and Report Invasive Species (iNaturalist and Report Invasives BC)